The more I think about it, it's like the car grounded out and drained everything.

Sounds like you're having the same problem I was having. When I turned the key to the accessory position (first click), the radio and lights all came on fine. When I went to start the car, everything went black.

Turns out it was a bad connection on the negative battery terminal (could happen just as easy on the positive side). Cleaning the battery post and the clamp worked for a little while, but eventually I had to change the clamp.